Cave Johnson was gradually getting on Doc's nerves. The more he spoke, the more he talked about things that had gone wrong with testing. His over-confidence didn't make the situation better. It was almost as if this guy was happy that he'd forced thousands of people through these ridiculous tests. There was no point in completing these tests - nobody was around to see it - but they had no choice. After each test, an elevator brought them closer and closer to the surface … and to home.

Eventually, they came across another pump station, this one labeled "Beta". Two sets of pipes ran through it. The first set was painted with blue arrows, clearly containing repulsion gel. The second set had orange arrows on it. Doc had noticed that the colours blue and orange seemed to reoccur throughout both this facility and the new one. At least, they kept to a colour scheme.

At the top of the station was a small office. It didn't look as though they would be able to reach the office from where they were. Doc placed some portals, allowing them to reach a platform. He could see two white sections of the floor below them: one directly underneath them, the other was a bit further off. The scientist placed a portal on each of these white panels and jumped in.

He was sent flying straight upwards, facing a slightly different direction. From there, he could see another white portal on the wall. He attempted to fire a portal on that, but gravity pulled him back down again and through the portals.

From Marty's point of view, this looked hilarious; Doc was effectively falling upwards between portals and it looked absolutely bizarre. He couldn't help but laugh, especially because his friend's mane of white hair was being thrown around too.

Doc successfully managed to place a portal on the wall and he sailed across to the office. Marty was still chuckling. "Like an eagle… piloting a blimp!"

Doc's snort of laughter could be heard from across the room. Leaning over the edge of the door, the scientist placed a portal on the panel beneath Marty, allowing him to jump through and join him. "Come on you,"

Marty rolled his eyes. On the desk in the office were two levers, one blue and one orange. They both pulled a lever and the familiar flowing-liquid sounds came from the pipes. The door slid open and they were able to progress. They walked through another door and into a large chamber. A building was at one end with some broken stairs leading into it. Cave Johnson was talking again.

"Hello, I'm Cave Johnson, CEO of Aperture Science. You may remember us as a vital participant in the 1968 senate hearings on missing astronauts, and you've most likely used one of the many products we've invented, but which other people have somehow managed to steal from us. Black Mesa can kiss my bankrupt -"

"Sir?" Caroline's voice cut him off. "The testing,"

"Right. Now, you might be asking yourself: Cave, just how difficult are these tests? What was in that phonebook of a contract I signed?"

He appeared to be repeating the same sort of nonsense again, so Doc and Marty ignored him. They noticed an elevator shaft on the ceiling, but the gate leading to the walkway was shut. They spotted an office in the building, but the broken stairway meant that they wouldn't be able to get there on foot. It seemed as though they would have to use portals again to get up there.

That's exactly what they did. They placed some portals and managed to reach the upper level of the building. As they walked into the office, they noticed a crow sitting in a nest. It appeared to be pecking at something, and that something was shouting!

"GET OFF ME!"

Marty gasped and ran over. The bird flew off, revealing a slightly bashed potato sitting in the nest. "GLaDOS?!"

"Oh, thank God," the potato emitted a robotic sigh of relief. "I thought I'd be eaten!" The room suddenly shook rather violently and the sound of a distant explosion could be heard. "Did you hear that? That little idiot doesn't know what he's doing up there. This whole place will blow up if we don't get me back into my body."

Doc cringed. "This isn't good…"

"Look, I understand you don't want to help me, but we're at an impasse. Unless one of you is prepared to saw your own head off and wedge it into my body, you're going to need me to replace him. I can't move, would you mind picking me up?"

Marty carefully picked the potato up. In doing so, he released the button that the potato had been resting on. A siren went off and Doc noticed that the gate was open. He looked at the potato in Marty's hands. "There's a risk that she will be destroyed by the emancipation grid if we bring her through,"

Marty frowned. "Then we'd really be screwed."

Doc carefully took the potato from Marty - and jammed it roughly onto the end of the portal gun.

"OW!" GLaDOS yelled. "You stabbed me! What is wrong with - whoa...!"

"What's wrong?" Marty asked. He looked the potato over.

"The gun must be part magnesium. It feels like I'm outputting an extra half a volt." GLaDOS replied. "I'm going to do some scheming. Here I go-" The potato went silent, emitting only a faint spark. Marty noticed that the optic had dimmed.

"She must have overpowered the potato," Doc explained. "It can only generate a very limited amount of power. She'll be fine in a minute,"

Marty ran a hand through his hair and nodded. Doc placed some more portals and they returned to the broken walkway. The teenager walked towards the office on the side. "Hey, check this out,"

Doc shrugged and followed him, looking around the office. Papers were littered everywhere and the scientist was reminded of his lab back home. Marty found a door partially hidden by a set of drawers and as he walked over to it, it slid open.

"What's that?" Doc called.

"I don't know, it's a passageway, come on!" Marty called back. The pair walked down the corridor and came to the only open door at the end. Going through it, they reached what looked like some sort of dockyard. "Hey, Doc? What's the 'Borealis'?"

Doc turned his head to see a lifeguard ring lying against the wall. Sure enough, the word 'Borealis' was painted on it. "I can only assume it was some sort of ship. It appears to be gone, though. Whoever was here must have removed it."

"But who would need a ship this far underground?" Marty asked.

"Whoa," GLaDOS's voice suddenly came back, and the potato's optic lit up again. "How long have I been out?"

"Only about a couple of minutes," Doc replied.

Marty frowned and looked back at the ring. "What on Earth happened down here?"

"Don't know, we'd better keep going. Best not to dwell on it,"

"Last I heard," GLaDOS piped up. "Was that this ship disappeared. Apparently the people building it wanted to beat another company to get some funding and they compromised a lot of basic safety rules. The ship vanished,"

Marty cringed. "Geez, as if this place wasn't freaky enough,"

"Let's keep going. We can't be that far from the surface now, surely," Doc lead Marty back down the passage. They placed a portal at the bottom of the chamber directly below them and another high up on the wall behind them. Jumping through, they landed just in front of the elevator. They got in and the door shut. The elevator shuddered and rose slowly upwards.

"I'd better not think too hard," GLaDOS murmured. "Otherwise, I'm going to fry this potato before we get a chance to burn up in the atomic fireball that LITTLE IDIOT IS GOING TO-" Another burst of static indicated that she had indeed just fried the processor in the potato again. The pair just let her recover.

Marty couldn't help but think about the crew on the Borealis. Something had happened to that ship, he just didn't know what. GLaDOS had mentioned that it had been unsafe, so maybe it sprung a leak and sunk. He still had no clue who this 'Black Mesa' company were that Cave had mentioned. There was clearly more to this future than he had first thought.

Despite the fact that he hated this place, he didn't fancy the idea of going back. Wheatley was there. If the moron was angry enough to force them down a broken elevator shaft, then it was likely he would kill them. Even though he was a moron, he most likely remembered taking out the neurotoxin generator as well as the turrets. The teenager had a feeling that those two items were going to become obstacles again.

The lift came to a halt beside another testing chamber and Cave Johnson's voice came out over the speakers again. "The testing area is just up ahead. The quicker you get through, the quicker you get your money."

"Hold on, who is that?" GLaDOS was clearly operational again.

Cave could be heard muttering something in the background.

"Yes sir, Mr Johnson," GLaDOS said. "Hold on, why did I say that? What the hell is going on here-"

Marty sighed. "She fried the damn thing again, didn't she?"

Doc nodded, smirking slightly. He noticed that there was a button on a platform and once he'd placed some portals, he was standing beside it. He saw that a pipe would eject some orange gel. From his vantage point, he could see just where the gel had to go. "Marty, get out the way!" He called. "Otherwise, you'll get soaked in this gel,"

Marty nodded and stood off to one side. Doc placed a portal beneath the pipe and another one on the wall facing a ramp. He pressed the button. Gel poured out of the pipe and slid along the floor, covering a strip of the floor and the ramp. The teenager walked onto the gel and started sliding around rather quickly. He fell flat on his backside, to which Doc laughed.

Marty shot him a glare. "I'd like to see you do better,"

Doc smirked and jumped down. He walked onto the gel and slid around with relative ease. "You know, for a kid who spends eighty percent of his life on a skateboard, you're pretty bad at this,"

Marty got to his feet and gave Doc a hard shove, causing the scientist to slip away. The gel had the same effect as an ice-skating rink, allowing them to get up to speeds higher than either of them could run. Marty ran towards the ramp and sailed over the gap, easily landing on the other side. Doc joined him.

There was another white panel on the wall beside them. Doc placed an orange portal there and a blue one above the platform where the button was and jumped through. Marty fell through after him.

"Whoa…" Marty groaned as he landed unsteadily on his feet. "I'm never going to get used to that,"

Doc chuckled and placed the blue portal below the pipe. He pressed the button again and saw that the gel now covered the corridor that they had been in previously. He jumped back through the portal and slid along the corridor, passing over the gap and reaching a cube. He grabbed the cube and made his way back over to Marty, placing the cube on the large button. The ramp adjusted in height, allowing them to reach the door.

The door was shut. Marty sighed. "Now what?"

Doc gestured to a white panel and some arrows pointing upwards. "Something tells me one of us has to use that gel and get up there." He looked at his teenage friend. "Would you do the honours?"

Marty rolled his eyes and, once Doc had placed the portals, went back over to the other side. He ran on the propulsion gel and was sent flying straight upwards. At the top of the jump, he managed to slam his hand down onto a button. He landed on the ground and the door slid open.

The pair walked through the door just as GLaDOS rebooted again. "Okay, I guess emotional outbursts like that require more than 1.6 volts." Marty held back a snicker at the thought of his friend exclaiming just how much power was needed for the flux capacitor to work. "Now we know that we just have to relax."

"That's easy for you to say," Marty pointed out. "You're just sitting there while we do all the work,"

"It's not like I have a choice, you know," GLaDOS snapped. "And from what I can tell you're not doing much work. It appears that Emmett is the one doing everything. Have you always been this much of a slacker?"

Marty growled. "I would be helping him if it weren't for the fact that my hands are still burnt and my left arm hurts like hell!"

"The only reason you're injured is because of your own stupidity," GLaDOS retorted. "Perhaps if you spent less time being so useless and more time actually paying attention you wouldn't be hurt,"

Marty made a move to grab the potato but Doc pulled the gun out of his reach, holding it above his head. Marty jumped up and tried to grab it, but he was too short. "God DAMNIT Doc!"

Doc fixed him a stern look. "Marty, cut it out. Fighting in a situation like this will get us nowhere. Like GLaDOS said, we have to stay calm,"

"You expect me to be CALM?!" Marty shouted. "We got stuck here, locked in a room, forced through some tests, been thrown in front of talking machine guns, been put in front of lasers and shoved down an elevator shaft! We have no idea where we are or how to get out of here! We're STUCK!"

"Freaking out and shouting will not help!" Doc snapped. "Now why don't you just take a deep breath and calm the hell down."

Marty growled, sucking air in through his teeth. He narrowed his eyes. "The only reason we're stuck here is because you decided to modify the DeLorean AGAIN! Why can't you just leave that fucking thing alone?!"

"Because it's the only thing I've ever built that has ever been worthwhile!" Doc shouted. "Everything else has just been a failure,"

"No wonder," Marty muttered under his breath. "They've all been failures 'cause they were built by a madman!"

"ENOUGH!" Doc shouted. "Listen, we can have this argument later. Right now, let's just focus on getting back to the main facility,"

Marty muttered something incoherent under his breath again and shoved his hands in his pockets. Doc let out a frustrated growl and kept walking, the teenager trudging along behind him.